By way of introduction, TV program regulatory authorities, such as the CSA of France, require operators to support parental control in such a way as to prevent the viewing (or hearing) of programs for which parental control is critical, in an automatic fashion. In most countries, parental control is realized through the analysis of digital information that is transmitted by operators along with the programs. The digital information, which indicates the level of criticality of the programs, is generally transmitted along with other digital data containing the program title, synopsis and so on. All of the information is typically consolidated, for example, in an Event Information Table (EIT), such that parental control is realized through an analysis of the EIT data.
Parental control based on EIT analysis poses a number of problems. One problem is due to inadequate synchronization of the EIT data with the broadcast of the programming content. Inadequate synchronization can result in a non-authorized person viewing, in whole or in part, programming content for which parental control is critical.
Another problem lies in the standard EIT cycle time, which is generally two seconds. In order for parental control to be successful during channel surfing, the EIT data is first received prior to display of the video image, thereby causing a delay between zapping and display of the video. Many users regard the delay, which may be up to approximately two seconds, as being unduly long.
The following references are also believed to represent the state of the art:    U.S. Pat. No. 4,908,859 to Bennett, et al.;    U.S. Pat. No. 5,969,748 to Casement, et al.;    U.S. Pat. No. 6,020,882 to Kinghorn, et al.;    US Published Patent Application 2003/0233651 of Farley, et al.;    US Published Patent Application 2005/0166235 of Mears, et al.;    UK Patent Application GB 2 349 290 of NDS Limited; and    Japanese Patent Application Abstract JP2001202748 of Victor Company of Japan.
The disclosures of all references mentioned above and throughout the present specification, as well as the disclosures of all references mentioned in those references, are hereby incorporated herein by reference.